Steam-pump.



W. ATTWOOD.

SSEAM PUMP.

APPucATmN FILED wu'zs, 191s.

' 1.3%930 Patented Oct. 3,1916.

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Inventor. 97mm W. ATTWOOD.

STEAM PUMP.

APPLICATION FILED JULY 28. 1915.

Patented Oct. 3, 1916.

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UNITED STATES STEAM-PUMP.

Specification of Letters Patent.

Patented Oct. 3, 1916.

Application filed July 28, 1915. Serial No. 42,458.

' York, Province of Ontario, in the Dominion of Canada, have invented certain new and useful Improvements in Steam-Pumps, as.

described in the following specification and illustrated in the accompanying drawings, that form part of the same. i The objects of the invention are to improve and simplify the automatic controlling mechanism of direct acting steam pumps insuring very positive action and further to reduce the cost of manufacture.

The principal feature of the invention consists in the novel construction and arrangement of parts, whereby the main controlled by the movement of the piston.

In the drawings, Figure 1 is a longitudinal vertical section of the steam pump cylinder and valve chest. Fig. 2 is avertical cross sectional view through the line A.B of Fig. 1. Fig. 3 is a vertical cross sectional view through the line CD of Fig. 1.

Like numerals of reference indicate corresponding parts in each figure.

Referring to the drawings, 1 is the steam cylinder having the inlet and outlet ports 2 and 3 arranged adjacent to the ends and preferably at one side of the vertical: center, said ports extending inwardly and upwardly to the valve seat l and communicating with the steam chest 5 and with the exhaust port 6.

7 is a valve casing secured to the upper face of the cylinder having the cylindrical valve chambers 8 and' 9 arranged preferably one directly over the other- 10 is a pipe connection leading to the steam chest 5 formed in the central part of the lower valve chamber-8 which communicates with the inlet ports to the cylinder. The valve chambers 8 and 9 are each closed at the ends by suitable caps.

11 is a piston valve operating in the valve chamber 8 and preferably formed hollow having a reduced central portion 12 which is adapted to receive the slide valve 13 operating upon the valve seat 4.

The reduced central portion of the valve 11 is formed with a central longitudinal slot 14 in the underside to receive the up wardly extending web 15 of the slide valve which thus forms a positive connection therewith and is also provided with slots 16 in the sides which allows of a free ingress of steam to the interior of the valve from the steam chest.

17 are small bleed holes in the ends of the piston valve 11 allowing steam pressure to leak through from the steam chest into both ends of the valve chamber 8.

18 are annular grooves formed in the piston ends of-the valve 11 intermediate of their length,

19 are port openings through the valve casing 7 communicating with the main cylinder and the valve chamber 8 and each arranged to communicate with the grooves 18 in the valve when said valve is at the limit of its stroke at either end.

20 are ports leadingfrom the top side of the valve chamber 8 and arranged in the same transverse plane as the ports 19 and communicating with the valve chamber 9 closely adjacent to the ends.

21 is a piston valve arranged-in the valve chamber 9 having a reduced central portion 22 forming an annular chamber 23 whichis connected by a suitable passage 24: to the exhaust port 6.

25 are passages formed in the walls of the valve casing leading from the valve chamber 8 at. alpointadjacent to the ends and communicating with the valve chamber 9 at a point adjacent to the chamber 23. The openings of said passages into the chamber 8 are adapted to be closed by the piston valve at the outward end of its stroke and cleared by the opposite end of the piston and the other end of the passages entering the valve chamber 9 are alternately opened and closed by the valve 21, that is to say, when either of the passages is opened at the chamber 8 the end in the chamber 9 is closed at the end entering the chamber 8 and open at the chamber 9. The ports entering the steam cylinder are arranged to be opened just prior to the piston reaching the limit of its outward stroke and the live steam in the cylinder flows upwardly through said ports and the groove 18 in the valve 11 and port 20 to the end of the valve chamber 9. The pressure of steam against the end of the valve 21 forces this valve to the opposite end of the chamber and the passage 24 leading from the chamber 8 is thus opened to communicate with the exhaust and the steam pressure is immediately reduced. This quick reduction of steam pressure at one end of the piston valve 11 allows of the pressure at the opposing end moving the valve rapidly to the reverse position.

26 and 27 are cross over ducts arranged in the valve casing 7 leading upwardly from the ports 2 and 3 respectively. The upper end of the duct 26 opens inwardly into the valve chamber 8 and is spaced a short distance from the port 20 at one end, the open end of the duct being the same width as the annular groove 18 in the piston valve and the distance between the outward side of the said opening and the inward side of the I: port 20 being practically the same width as the groove 18.

28 are passages formed in the piston valve 11 communicating with the grooves 18 and adapted when the said grooves 18 are in communication with either of the ports 26 and 27 to form a communicating passage between the said port 26 or 27 and the port 20.

The opening in the port 20 is spaced in an exactly similar location to the opening of the port 26 so that as the piston valve 11 moves from either one end or the other the steam from the cylinder is first cut off by moving the groove 18 out of alinement with the port 19 and the said groove then moves into communication with the correspond ing port 26 or 27, thereby opening an exhaust at the end of the valve chamber 9 coincidently with the opening of the steam passage through the port 19, groove 18 and port 20 at the opposite end, thus allowing the free movement of the piston valve 21.

The operation. of the pump is extremely simple. hen the steam is turned into the steam chest it flows through either of the ports 2 andS to the cylinder and operates the piston. As the piston moves to the end of its stroke it uncovers the port 19 with which the groove 18 in the piston valve 11 is in register and the steam flows immediately to the valve casing 9 forcing the piston valve 21 to the opposite end. This movement closes the end of the passage 25 leading from one end of the valve chamber 8 and opens the passage from the opposite end. The steam in the steam chest enters the interior of the valve 11 and fills the ends of the valve chamber 8 with the steam through the holes 17 and upon the opening of the passage 25 the steam in the end is exhausted to the central portion of the chamber 9 from which it flows through the passage 24: to the exhaust.

Upon the exhaust of the steam pressure from one end of the pump the pressure at the opposite end forces the valve 11 to its opposite position changing the steam inlet and exhaust to the cylinder and opening up the opposite exhaust arrangement from the valve chamber 9 and also opening the steam inlet to the opposite end of the valve chamher 9 so that when the piston moves to the opposite end of its stroke, the live steam will pass through the chamber 9 and operate the valve therein in its return movement.

A very important feature in the construction herein described is that the pilot piston valve 21 is definitely controlled at the ends of the stroke and held from fluttering by steam pressure introduced at the moment of the cross over on the center of the stroke of the main valve from the inlet to exhaust. It will be noted that the cross over ducts 2,6 and 27 communicate with the ports 2 and 3 respectively and cross over the center of stroke and communicate with the grooves 18 at the opposite ends from the ports 2 and 3. The result obtained by reason of this ar- .rangement' is that when the slide valve 18 moves longitudinally it first cuts off the live steam supply to the port 2 or 3 as the case may be, the movement being caused by reduction in pressure at one end of the valve 11 through the initial movement of the valve 21. The port ends of the ducts 26 and 27 are arranged in such a position'that the grooves 18 commenceto open the ports to said ducts coincident with the opening of the port 2 or 3 to the exhaust, consequently the initial pressure of exhaust flows through the said duct to the groove 18 and through the passage 28 and port 20 to the end of the valve chamber 9, thus temporarily intro ducing a pressure behind the piston valve 21 following the exhaust of the live steam pressure and preventing the pilot valve from rebounding upon reaching the limit of its stroke. This action is instantaneous occurring at the moment of the opening of the exhaust and effectually prevents fluttering i be manufactured at very low cost.

What I claim as my invention is V,

1. In a steam pump, the combination with the steam cylinder, piston and steam chest, of a cylindrical valve chamber in communication with said steam chest, a piston valve operating in said chamber and controlling the flow of steam to and from the cylinder, said piston valve having an open center in communication with the steam chest and openings through the ends and balancing said valve, and a steam actuated piston valve controlled by the movement ofthe piston adapted to eliect the reduction of steam pressure at either end of the main valve to cause the said main valve to be operated.

2. In a steam pump, the combination with the steam cylinder, piston and steam chest, of a cylindrical valve chamber in communication with said steam chest, a piston valve operating in said valve chamber and controlling the flow of steam to and from the cylinder to operate the piston, said valve having openings through the ends communicating with the steam chest, a secondary valve chamber having an exhaust opening therefrom, ports leading from the ends of the controlling valve chamber to the secondary valve chamber, said ports being of greater cross sectional area than the openings in the ends of the controlling valve, a piston valve in said secondary chamber adapted to close either one of said ports and to open the other to the exhaust, and ports leading from the steam cylinder to the secondary valve chamber and controlled by said controlling valve.

3. In a steam pump, the combination with the steam cylinder, piston and steam chest, of a cylindrical valve chamber in communication with said steam chest, a piston valve operating in said valve chamber and controlling the flow of steam to and from the cylinder to operate the piston, said valve having openings through the ends communicating with the steam chest, a secondary valve chamber having an exhaust opening therefrom, ports leading from the ends of the controlling valve chamber to the secondary valve chamber, said ports being of greater cross sectional area than the openings in the ends of the controlling valve, a piston valve in said secondary chamber adapted to close either one of said ports and to open the other to the exhaust, ports leading from the steam cylinder to the main valve chamber and covered by the main valve, ports leading from the main valve chamber to the ends of the secondary valve chamber, passages formed in the main piston valve adapted to open communication between the steam cylinder and secondary valve chamber ports, and means for exhausting the steam from the ends of the secondary valve chamber.

4. In a steam pump, the combination with .valve chamber, said ports being of greater cross sectional area than the openings in the ends of the controlling valve, a piston valve in said secondary chamber adapted to close either one of said ports and to open the other to the exhaust, ports leading from the steam cylinder to the main valve chamber and covered by the main valve, ports leading from the main valve chamber to the ends of the secondary valve chamber, passages formed in the main piston valve adapted to open communication between the steam cylinder and secondary valve chamber ports, ports opening from the main valve chamber adapted to communicate with the passages in the piston and communicating with the exhaust, and ducts leading from said passages in said valve adapted to communicate with the ports to the secondary valve chamber when the ports from the cylinder to the main valve casing are closed.

5. In a steam pump, the combination with the steam cylinder, having main inlet and exhaust ports and ports adjacent to the ends controlled by the piston, of a unitary valve casing having a combined steam chest and main valve chamber communicating with the cylinder ports and a secondary valve chamber of lesser length than the main valve chamber, ports leading from the ends of the main valve chamber to the secondary valve chamber, a piston valve adapted to close said latter ports or to open them to exhaust, ports leading from the main valve chamber to the ends of the secondary valve chamber, and a main piston valve adapted to bring the latter ports into communication with the ports leading to the main valve chamber from near the cylinder ends or to open same to exhaust, said main piston valve having bleed openings in the ends communicating with the steam chest.

6. In a steam pump, the combination with the steam cylinder having the usual combination inlet and exhaust ports leading to each end from the steam chest, of a cylindrical valve chamber in communication with said steam chest, a piston valve operating in said valve chamber and controlling the flow of steam to and from the cylinder to Opel: ate the piston, a secondary valve chamber having communicating ports from the main valve chamber, a piston valve operating in said secondary valve chamber to control the movement of the main valve, ports leading from the steam cylinder to the main valve chamber and covered by said main valve, annular passages in said main valve adapted to communicate with said ports from the steam cylinder, ports leading from the main valve chamber to the ends of the secondary valve chamber and arranged in transverse alinement with the ports to the main valve chamber from the cylinder, cross-over ducts communicating with the exhaust passages from the main cylinder and extending longi-' tudinally in the main valve casing crossing over the center line of the stroke of the valve and having ports entering the main valve chamber so arranged as to communicate with the annular passages in the main valve simultaneously with the cutting off of the live steam to the opposite end of the steam cylinder and coincident with the openmain valve chamber to the secondary valve chamber to establish a communication between the end of the secondary valve chamber and the exhaust at the moment of opening of the main exhaust, as and for the purpose specified.

Signed at Toronto, Ontario, Canada, this 29th day of June 1915.

WALTER ATTWOOD.

Copies 01' this patent may be obtained for five cents each, by addressing the "Commissioner of Patents, Washington, D. C. 

